docs: def save_dataframes(self, outdir, prefix='df_'):
          """Save all attributes that start with "df" into a specified directory.
  
          Args:
              outdir (str): Path to output directory
              prefix (str): Prefix that dataframe attributes start with
  
          """
          # Get list of attributes that start with "df_"
          dfs = list(filter(lambda x: x.startswith(prefix), dir(self)))
  
          counter = 0
          for df in dfs:
              outpath = ssbio.utils.outfile_maker(inname=df, outext='.csv', outdir=outdir)
              my_df = getattr(self, df)
              if not isinstance(my_df, pd.DataFrame):
                  raise TypeError('{}: object is not a Pandas DataFrame'.format(df))
  
              if my_df.empty:
                  log.debug('{}: empty dataframe, not saving'.format(df))
              else:
                  my_df.to_csv(outpath)
                  log.debug('{}: saved dataframe'.format(outpath))
                  counter += 1
  
          log.debug('Saved {} dataframes at {}'.format(counter, outdir))